Steam is a game distribution and sales platform by Valve Software, that most PC gamers get their games from. Until now they only sold games and updated them, along with providing a community and achievement system, but they announced that you can start buying non-game software. The selection of titles is small but is more focused on creative users. The list includes the following
The titles also integrate with the Steam Cloud to save your files to. Also GameMake Studio lets you upload to the Steam Workshop that let other users on steam play the games you make in the software.
Also from October 2nd to 9th you can get 10% off of all these titles as a promotion of the new Software.